This article provides an exhaustive deep dive into , explaining what it means, when to use it, how to interpret its tables, and its real-world implications for CNC machining, quality control, and design engineering. What is ISO 2768? Before focusing on the "mk" classification, it is essential to understand the parent standard. ISO 2768 is an international standard titled "General tolerances for linear and angular dimensions without individual tolerance indications."
In the world of technical drawing and mechanical engineering, specifying every single dimension with a unique tolerance is impractical, time-consuming, and clutters the blueprint. This is where general tolerances come into play. Among the most widely recognized standards globally is ISO 2768 , and within that standard, the specific class "mk" represents a critical balance between manufacturing cost and precision. general tolerance iso 2768-mk
| Nominal Length of Shorter Side (mm) | Tolerance (mm per meter) | Tolerance (degrees/minutes) | | --- | --- | --- | | Up to 10 | ±1° | ±1° | | >10 to 50 | ±0°30' | ±0°30' | | >50 to 120 | ±0°20' | ±0°20' | | >120 to 400 | ±0°10' | ±0°10' | | >400 | ±0°5' | ±0°5' | This is where ISO 2768-mk becomes stricter than the 'f' (fine) class. Class 'k' tolerances are tighter than 'L' (coarse) but looser than 'H' (precision). The values depend on the nominal length of the feature. This article provides an exhaustive deep dive into